Slab foundation Swedish slab. USHP foundation (insulated Swedish plate)

The construction industry does not stand still. Manufacturers strive to produce improved materials and offer new technologies, thanks to which they can not only reduce the cost of construction, but also improve the technical performance of the final product. One of the latest developments, which originated in Sweden, is the USP foundation - a technology for economical and quick construction of the foundation for a private house or two-story cottage.

Currently, there are three types of slab foundations, each of which has its own distinctive features. The Russian version, which was designed by domestic designers, is considered traditional. The product is a thick monolithic reinforced concrete slab with massive ribs. The foundation is characterized by a large strength reserve and lack of deformation, due to which it can be used under extreme operating conditions.

The disadvantages of the design include insufficient insulation and the need to pour concrete twice: the first - to create stiffeners, the second - to form the slab itself. However, this increases the service life.

The foundation is in the form of an insulated Finnish slab, originally from Finland. The design has a smaller thickness, but is characterized by sufficient strength. It is well insulated and adapted to a heated floor system. Such a foundation is a cold circuit. Thermal insulation with a thickness of at least 150 mm is mounted on the slab, cutting off the cold contour of the foundation from the warm floor of the first floor of the building, which is installed in an additional reinforced screed.

Less energy-saving, but more economical compared to the Finnish version, is the insulated Swedish stove. USHP does not require additional screed, since the heated floor system is mounted directly into the slab, the thickness of which reaches a minimum size.

What is USP: areas of use

The insulated Swedish foundation slab is represented by a shallow monolithic slab foundation. It has insulation along the entire perimeter and sole area. This is a finished rough floor surface of the first floor with built-in heated floor and utilities.

This type of foundation is used in building projects without a basement or basement. It is advisable to use USHP technology for structures with a side size of 15 m in the following cases:

for cold regions where, thanks to such a foundation, heat loss from the house is reduced;
in areas with high groundwater levels;
in projects of private houses where heated floors are used;
in the case of application, as well as in the process of creating a panel, panel or frame house;
when choosing block or brick masonry;
on heaving and weak soils that are not characterized by good bearing capacity, which requires the construction of bored or screw foundations.

USHP foundation design: cross-sectional photo of the product

The structure consists of the following layers, which are clearly shown in the cross-sectional drawing of a Swedish foundation slab:

concrete pouring;

reinforced layer;
depreciation layer;
insulating layers.

A concrete pour, or monolith, is represented by a conventional foundation with a thickness of only 10 cm, thanks to which the structure is created in one day. This has a positive effect on the quality of the slab, namely: layering is eliminated and the cost of work is reduced. A heated floor system is laid in this layer. The base is insulated from the ground with insulation, which is represented by extruded slab polystyrene foam.

Reinforcement is also carried out in a short time due to the use of a small number of metal rods. A tightly knit reinforced mesh prevents cracking of concrete and prevents damage to the foundation due to natural soil movement.

The traditional depreciation layer, consisting of sand and crushed stone, which is used in a conventional foundation, is supplemented using this USP technology with a layer of clay. Thanks to this, geotextiles laid between mineral layers are not exposed to moisture. An additional waterproofing layer in the foundation is necessary in order to protect the structure from the influence of groundwater, which can erode the layers. In the thickness of the sand under a layer of insulation, sewerage and a water supply system are installed, the nature of which affects the price of the USP.

To create a durable and strong structure, it should be insulated, so that the foundation will not crack and heave during temperature fluctuations. The process is carried out using styrene derivatives, as a result of which the service life increases several times. The insulation is laid not only from below, but also vertically along the perimeter of the slab, duplicating the base formwork. Also, the layer is located under the blind area of the building horizontally at the depth of the base of the reinforced concrete structure. This technology increases the cost of USHP, but reduces further costs for heating the room.

Drainage communications are necessary to create a system for removing moisture from the foundation, which prevents it from damage. A waterproofing layer with vapor barrier properties protects concrete from moisture.

Advantages and disadvantages of USP foundation

The USHP foundation, which can be ordered from any large construction company, is characterized by a number of distinctive advantages:

low cost of work, which is associated with a small amount of building materials and the involvement of a small number of workers;

high speed performance;
thanks to the additional layer of insulation, the possibility of freezing of the soil under the base of the foundation is eliminated, which will save the slab from heaving and shrinkage of the base;
the foundation slab is a full-fledged subfloor on which tiles can be laid without first leveling the surface;
installing a heated floor in the foundation will reduce heating costs in the future due to lower thermal energy consumption;
the insulation is characterized by high compressive strength and shrinks the building by 2%;
the thermal insulation layer is not affected by moisture, which increases its service life;
due to the fact that the foundation is insulated, dampness and mold will not form in the house;
the appearance of insects and rodents is excluded in the insulating layer;
the small thickness of the thermal insulation layer provides the required thermal conductivity coefficient;
the presence of edges on the thermal insulation slabs eliminates the creation of cold bridges;
the plate simultaneously performs heating, thermal insulation and load-bearing functions;

has a durable design while maintaining all technical and economic characteristics;
due to its high heat capacity, it can be used in regions with cold climates.

Disadvantages of USP:

the foundation slab is created exclusively on a reliable foundation, which excludes its installation on muddy, peaty or vegetative soils;
a significant part of the engineering communications is located in the thickness of the slab, as a result of which access to them is limited;
USHP cannot be used in the construction of heavy multi-story buildings;
the foundation excludes the creation of a basement in the house.

The Swedish foundation consists of several layers, each of which has an important functional purpose. It is very important to properly organize each layer in order to obtain a reliable, strong and durable structure. There are important points to consider here. The thickness of the sand or gravel substrate is determined based on the type of soil, that is, it depends on its bearing capacity. This value is in the range of 300-600 mm, which affects the price of the USP foundation. For the hardest, densest soils, the minimum value is used, and for heaving soils, the maximum value is used.

Before building a slab foundation, the top layer of soil should be removed. Using a level and a building level, the verticality and horizontality of the surface is checked. The pit must have larger dimensions than the perimeter of the slab. For this purpose, it is necessary to retreat 50-70 cm from the edges of the base markings on each side.

Plates of insulating material should be laid over the entire surface of the foundation. It is not recommended to fasten them with additional adhesive. To create a uniform, dense layer, concrete pouring must be done in one go. Therefore, it is important to correctly calculate the amount of material required to fill the formwork.

Helpful advice! The best option for installing USHP is considered to be concrete of class B20-B25.

Before starting construction, pipes for all communications should be prepared and a diagram of their location should be developed. It is necessary to provide a drainage system along the perimeter of the foundation, which ensures the removal of moisture from the base of the building.

Survey work, USP calculation and terrain tracing

Survey activities precede the start of construction. They are carried out to determine the nature of the soil and its bearing capacity. The level of groundwater in the area, the composition of the soil and possible fluctuations in the lower layers of the soil are clarified. These indicators must be as correct and accurate as possible in order to subsequently provide a solid foundation. Therefore, here you should use the services of specialists.

The main difference between the calculation of an insulated foundation slab is the sequential determination of the parameters of each layer during construction, taking into account actual loads and impacts. For this purpose, special computer programs are used that determine the individual characteristics of the foundation.

Helpful advice! It is better to design a Swedish foundation with the involvement of professionals, which will avoid many errors in the calculations.

After all the preparatory measures have been completed, they begin directly to build the foundation. To do this, you should mark the territory, which is the drawing of full-scale axes. The contours of the pit are outlined along the ground, cast-offs are installed along which the cords necessary for installing the formwork are pulled. The main advantage of cast-offs (compared to conventional pegs) is the convenient U-shaped design, the position of which is leveled once in the horizontal plane. If the cord is temporarily removed when necessary, no adjustments are required once it is in place.

The pit should be planned larger than the foundation slab. An allowance of about 1 m should be left on each side. Such indents will be used for installing drainage. This can be a ring drainage to lower the groundwater level or a wall drainage used to drain high water, which is formed with the constant accumulation of rain and flood waters of the underlying layer in technogenic zones.

Related article:

Main stages of construction, important nuances. Budget projects based on various materials and the right ways to save.

List of required materials and tools

Doing USP with your own hands is not as difficult as it seems at first glance. Before starting work, it is necessary to have a design for a new building and determine the location for construction. You can, of course, use the services of specialists and order a turnkey USHP foundation. However, strict adherence to technology and the use of high-quality materials will allow you to independently create a solid and reliable foundation for subsequent construction.

List of materials required for the construction of the USHP foundation:

medium sand;
medium-sized crushed stone;
geotextiles;
extruded polystyrene foam 100 mm thick;
drainage pipes;
wooden boards;
reinforcement bars;
knitting wire;
pipes of different diameters for utilities and water heated floors;
nylon clamps;

To work you will need the following tools:

scoop and bayonet blades;
wheelbarrow;
level;

building level;
screwdriver;
Bulgarian;
deep vibrator;
hacksaw;
concrete mixer;
trowel;
protective clothing.

Excavation work and creation of a drainage system

A warm foundation cannot be laid on a plant layer whose thickness does not exceed 0.3-0.5 m, so it should be removed completely. To do this, you can use bayonet shovels. If the foundation is laid on a fertile layer, it will inevitably shrink, which will be a consequence of rotting organic matter.

Helpful advice! To be safe, it is recommended to treat the area cleared of vegetation with chemicals that stop further plant growth.

After sampling the soil, the surface must be compacted using clay, which, in dry crushed form, is poured into the pit, moistened and compacted. Next, geotextiles are laid. The ends of the woven fabric should protrude beyond the future foundation by at least 30 cm.

In order for the slab to always remain dry, it is important to properly organize the drainage system, thanks to which groundwater, storm water and melt water will be drained from the base of the foundation. For this purpose, it is necessary to make a trench along the entire perimeter of the pit with a depth equal to the diameter of the perforated pipes that will be used for drainage. Here you should slope away from the building by 3-4 degrees, which will ensure gravity flow. It is necessary to install vertical wells in the corners of the building, which will provide access to the drainage system for periodic cleaning.

The sequence of actions is as follows:

a layer of crushed stone is laid on the geotextile;
in the corners of the structure, wells are installed, which are created from solid smooth or corrugated pipes with a diameter of 20-30 cm, installed vertically;
installation of corrugated pipes along the perimeter of the building with the ends entering adjacent wells, where the corresponding holes are made;
filling the trench with crushed stone, which is covered with geotextile on top.

Laying out utilities and creating a shock-absorbing cushion

Next, they begin to arrange a shock-absorbing cushion about 15 cm thick from gravel or crushed stone with fractions of 20-40 mm in size. The base is filled with fine sand, which is compacted every 20 cm with a hand tamper or vibrator until the design mark is reached.

All utilities must be laid before creating a monolithic foundation, so they are placed on a sand cushion with compaction according to the wiring plan below the freezing level. All ends of the pipes must be brought to the surface for further connection of the system. To increase the maintainability of networks, it is better to lay pipes in cases of larger diameter. For the sewer system, a well should be provided outside so that sewer inspection and repair can be carried out.

Helpful advice! As a backup option in case of failure of the main communications, a duplication of the engineering system is created, which can be switched to when repairing the old one.

After laying all utilities, the surface is covered with a small layer of gravel up to 15 cm thick, followed by compaction. For good waterproofing, the base is covered with waterproof material. Here you can use both inexpensive roofing felt and more modern products. The canvases are laid with an overlap of 10 cm and the joints are sealed. The edges of the waterproofing material must protrude beyond the foundation by at least 15 cm.

Installation of a thermal insulation layer for a USHP foundation

Insulation of the foundation is an important measure, thanks to which heat does not escape from the building into the ground, and cold does not penetrate from the soil into the room. The insulation must have high strength. Therefore, in USP technology it is recommended to use slabs made of extruded polystyrene foam, which (due to the presence of graphite in their composition) are characterized by increased compressive strength.

Helpful advice! Expanded polystyrene can harbor ants and other insects. Therefore, the material needs additional protection. Here it is recommended to use broken glass, metal mesh or ceramic foam slabs.

The material in the form of slabs 10 cm thick must be laid in two layers. The first should cover the entire perimeter of the base and the blind area. The second layer should be laid offset from the edge by at least 45 cm, which will create stiffening ribs. In the middle of the slab, in the thermal insulation layer, grooves 20-30 cm wide are made for future load-bearing walls, under which the insulation does not fit.

When using flat sheets of insulating material, special plastic nails with wide heads are used to fasten them. The contact points can be treated with an adhesive composition. It is recommended to arrange the elements in a checkerboard pattern, which will help to avoid the formation of cold bridges at their junction points. You can also use l blocks for USHP, which are mounted at the ends of the structure. Having a special design, they do not require additional fastening during installation.

Which insulation is better to choose for the foundation?

Today, the construction market offers a wide range of insulation materials from well-known manufacturers, such as Technonikol, Stirex, Technoplex, Penoplex and URSA. The PSB-S material is not suitable for these works, since it is produced without a pressing stage.

The thickness of the foundation insulation is determined by many different factors.

Among all the proposed options, extruded polystyrene foam Penoplex occupies a leading position. The cost of the product is 1200 rubles/pack. The material is characterized by a number of distinctive advantages:

durability;
multifunctionality, since it simultaneously creates hydro- and thermal insulation;
environmental safety;
increased resistance to moisture;
not prone to the emergence of various microorganisms in the thickness of the layer.

Also no less popular is the insulation for USHP TechnoNIKOL. The material does not absorb moisture, does not shrink, does not swell, is characterized by a low thermal conductivity coefficient, exhibits chemical resistance and does not rot. To produce extruded polystyrene foam, TechnoNIKOL uses nano-sized carbohydrate particles, which increases the strength of the material, reducing its thermal conductivity, thereby increasing energy efficiency.

A very important task, therefore, when choosing a suitable material, it is necessary to take into account its characteristics

The material is characterized by high compressive strength and stable thickness under load, as a result of which it can be used for loaded structures. You can buy the material from 1400 rubles/pack, the cost of l blocks for USP is on average 1300 rubles/pack.

At this stage, wooden formwork is laid under the future monolithic tile. To do this, racks are mounted to which the edged boards are attached using self-tapping screws and a screwdriver. The wooden frame is additionally reinforced with braces to give the structure greater strength. The formwork is lined with heat-insulating material from the inside. After the slab has gained sufficient strength, the fence is dismantled, and the insulation remains as protective sides for the lower part of the building.

The value of a double layer of thermal insulation and a heated floor system for a home at USHP

Due to the fact that USHP technology requires laying thermal insulation material in two layers, all the heat will remain in the house. The first layer of 10 cm along the entire perimeter of the base prevents the penetration of moisture. Another 10 cm of thermal insulation creates a good barrier against the cold that comes from the ground.

Thanks to the underfloor heating system, which is installed in separate circuits in each room, uniform heat distribution in the room is ensured and climate zones are adjusted. If you create the necessary insulation of the walls and roof of the building, it will be enough to maintain the temperature in the heating system no more than 28 degrees, which corresponds to the temperature of the circulating fluid (31-32 degrees), in order to create a comfortable microclimate in the house. However, this also depends on the finishing floor covering. Such measures will provide an additional benefit when using low temperature heat sources such as gas condensing boilers and heat pumps.

Thanks to the foundation in the form of a warm Swedish stove, you can save about 30% on heating. This is possible due to the fact that the underfloor heating system heats the concrete slab, and the concrete accumulates heat into the room. The thermal conductivity coefficient is 0.17 W/m²K, and for non-insulated concrete bases it is 0.4 W/m²K.

Reinforcement of the Swedish slab foundation and installation of heated floors

Foundation reinforcement is performed to allow the structure to absorb tensile loads. The technology is performed according to the following scheme:

creation of stiffening ribs for the grillage: frames are laid from reinforcement 10-16 mm thick, connected with rectangular clamps 6-8 mm in increments of 300 mm, taking into account the protective layer of concrete;

slab reinforcement: installation between the stiffeners of two reinforcing mesh with cells 150x150 mm from rods 10-14 mm thick, cell width 15 cm with tying structural elements with twisted wire every 25-30 cm.

The thickness of the rods is selected taking into account structural, snow and operational loads on the surface. Utilities should not be installed in stiffeners. In order not to damage the insulation, it is recommended to assemble the spatial reinforcement frame separately, and then you need to lay it ready-made on special clamps in the grillage area where the frames are connected to each other. The mesh for the slab is tied on site. The lower structure is installed on PVC clamps.

The technology of the Swedish insulated slab involves the installation of a heated floor in the thickness of a monolithic foundation. The heated floor contour is laid on the upper mesh and secured with nylon clamps. In this regard, the thickness of the upper protective layer of concrete should be taken into account, which should be 50-70 mm. In places where load-bearing walls or doorways are located, pipes should be placed in sleeves made of durable material. There must be a distance of at least 10 cm between the pipes.

If the laying is more dense, this will not affect the efficiency, but will result in excess consumption of material. A distance exceeding 25 cm will impair the uniform distribution of heat over the surface. Near the walls, pipes must be placed more densely than in the central part of future premises. An indentation of about 15 cm should be made from the wall.

Important! The heating pipes of a water heated floor should be arranged in an insulated circuit for each room separately, which will allow each room to be heated independently of the others.

The distribution elements of the system are brought up and fixed on rods hammered vertically. The collector should be located in the place provided for by the design at a given height. To install it, four reinforcing bars 1.5 m long are driven into the foundation. A board is fixed to them and the collector is temporarily fixed. Heated floor pipes are connected to it. Where flexible pipes rise to the collector, they must be protected using a special corrugated pipe.

Important! The heating system must be tested for leaks by filling it with coolant.

USHP foundation: technologyconcreting the base

The final stage of installing an insulated foundation slab is pouring the base with concrete mortar. The important thing here is to do the process one time. To do this, you can use a concrete mixer truck with an installed concrete pump. The solution is evenly distributed over the surface using shovels and trowels. To obtain a uniform surface, the fill should not spread over a distance of more than 1.5 m in diameter.

Batch filling can be done at intervals of 1 hour. If it is necessary to interrupt for a longer period of time, work seams should be arranged. After resuming work, they are moistened with water and treated with a cement laitance primer. The solution should be compacted using a vibrating plate or deep vibrator.

To ensure that the final surface is smooth, the base is sanded. This is an important undertaking because the concrete slab is the floor of the first floor. Otherwise, you will have to spend additional money on a leveling screed.

Helpful advice! It is recommended to build a USP foundation at the end of summer, when the groundwater level drops.

During the hardening period of the base, proper care of the concrete surface should be provided. In hot weather, it is necessary to moisten the foundation and cover it from precipitation with plastic film. Stripping can be carried out after 48 hours at a temperature of 30 degrees, and after 5-7 days - in cold weather at a temperature of 10-12 degrees.

USHP turnkey foundation: priceworks

The insulated Swedish stove is a modern method of equipping the foundation, which is gaining popularity in private and cottage housing construction. Today, many construction companies offer high-quality and quick turnkey installation of USP, the price of which depends on the size of the base, location of the site, soil properties, list of works and customer wishes. It is calculated individually for each specific case. Using the USP calculator, which is easy to find on specialized sites on the Internet, you can also independently calculate the approximate cost of the work. Here you will need data such as the area and perimeter of the base, the height of the slab edge.

The main list of services includes the following activities:

preparatory work before the start of construction: site marking, soil excavation;
laying geotextiles;

installation of a sand and gravel cushion;
installation of all communication systems;
production and installation of formwork;
installation of thermal insulation and underfloor heating systems;
knitting a reinforcing frame from rods using knitting wire;
pouring concrete with compaction using a deep vibrator;
grinding the base.

Important! The cost of the USP foundation includes delivery of the necessary materials to the construction site.

Price sq. m of Swedish foundation slab starts from 5,500 rubles. The larger the footprint, the lower the cost. For example, the price of an insulated Swedish stove with dimensions of 150-200 m² will be 7,500 rubles, and with dimensions of 50-70 m² - 9,000 rubles.

Despite the fact that the cost of constructing a USHP foundation exceeds the cost of a traditional monolithic foundation, such a device in the future will allow significant savings on heating.

There are companies that offer an expanded range of services for the construction of turnkey UWBs. In addition to the standard list, you can order geological surveys. In this case, the cost of work with the material will be 7,500 rubles.

The use of insulated Swedish plate technology will help to significantly reduce material consumption and reduce the time allotted for construction. Thanks to the built-in heated floor, it will be possible to save on space heating due to the high energy-saving characteristics of this type of base. To get a high-quality and durable foundation, it is recommended to order USP from specialized companies.

Foundation construction technologies vary and are used depending on many conditions - the nuances of the soil, climate, and the characteristics of the object. A monolithic slab is considered the most durable and reliable. However, it often becomes unacceptable due to the cost - up to 50% of the total budget allocated for construction, taking into account the combination of the price of concrete and the use of equipment. There is a way out - to install a slab under the future house

USHP is a new word in foundation construction. Let's look at it in detail.

USP technology foundation

Like any other foundation, USHP (insulated Swedish plate) is a “pie” of numerous building materials. These include:

Concrete pouring.
Reinforcement.
Shock-absorbing layers.
Hydro- and thermal insulation.

That's it in a nutshell. In addition, utility lines and heated floors run through the foundation.

Now more details.

Monolith

Unlike the classical one, the USHP technology provides a small but sufficient layer of concrete for the rigidity of the entire structure - from 10 cm. Due to the small thickness, pouring occurs in one day, which has a positive effect on the quality of the foundation - there is no layering, and on the cost - no need to use mixer several times.

Reinforcement

The amount of steel rod is also reduced, but this does not affect the strength of the foundation - the two planes of the mesh are connected to each other, preventing damage to the foundation during compression and bending. Concrete cracking is excluded, unlike classical technology.

Cushioning layers

Crushed stone and sand traditionally serve in this capacity, but in a classic slab they are layered on top of each other. In USHP the order of installation is different. In addition to sand and crushed stone, there is clay - the main “lock” for moisture and geotextiles laid between mineral layers. Additional waterproofing serves as an obstacle to groundwater - if the sand is not covered, it will come close to the insulation, which is unacceptable.

Insulation layers

For reliable operation of the foundation, it is necessary to protect it not only from moisture, but also to insulate it. Temperature changes can create condensation, cause heaving and cracking. The insulation, as a rule, is styrene derivatives - it reliably copes with the assigned tasks, extending the shelf life of the platform by 1.5–2 times in comparison with a classic monolith.

USP problems

It is quite clear that a house built on a USHP foundation will become ergonomically advantageous - less resources are required to heat the building, and accordingly, bills for heat or electricity consumption will no longer be exorbitant. Nevertheless, there are disadvantages, considering which it is worth thinking about the advisability of using this type of foundation. So:

The foundation is applicable for the construction of “light” houses - half-timbered frames, frames, OSB boards. As a last resort, it is allowed to use blocks or brickwork. You should also take a responsible approach to the choice of roofing material.
USP is used in relatively cold regions of the country. For mild or average climates it is not advisable to use it due to too high heat capacity. It can be harmful, as it threatens discomfort, mold formation, and loss of structure rigidity.
The foundation is suitable for high groundwater levels and capricious soil - heaving, floating. This is also typical for a classic stove. Otherwise, it is poured if the number of floors of the house is large or the construction material is heavy.
It is not recommended to install USP on difficult terrain. The soil has the property of movement, so for the structure this is fraught with a violation of the integrity due to the small layer of concrete pouring.
Having carefully analyzed the site and the architectural plans of the facility, or done this with the help of specialists, they come to the conclusion about using or not using the Swedish insulated slab as the foundation for their own home.

USP device technology - step by step

One of the advantages of the Swedish insulated board is the speed of installation and the ability to do everything yourself. The algorithm is as follows:

Site marking

To do this, you should project the contours on the ground in advance, in accordance with the plans of utility lines - they will pass through the thickness of the slab.

In addition, they take into account the importance of laying storm drains - water should not be allowed to approach the contours of the foundation. For work, stakes and a cord are used - the latter, for convenience, is painted in a contrasting color to accurately see the boundaries.

Digging and arrangement of the pit

Unlike a classic slab, the depth of the pit for installing a USP is small - 45–50 cm is enough. The owner has the right to hire equipment to remove soil, but the depth is quite suitable for manual processing.

An important condition is that the entire fertile layer should be removed, since the thickness of the soil with roots will attract moisture and create conditions for dampness and mold growth.

The perimeter of the USHP pit is larger than the boundary of the walls by at least 1 m. This value will include trenches for laying corrugated pipes for water drainage. Accordingly, they make a slight slope in one direction to ensure gravity flow. After sampling the soil, it is recommended to compact the leveled area with clay. To do this, dry and crushed material is sprinkled inside in an even layer and, after moistening, compacted.

Laying drainage pipes

The next step will be laying drainage pipes. To do this, the finished area of the pit is covered with geotextiles with the obligatory installation of the material on the walls of the pit and the ground plane above the trench. Before laying, the entire finished surface is covered with fine crushed stone, paying attention to the trenches for drainage - there the screening layer is compacted.

The pipes are laid and a layer of crushed stone is laid again. After which the surface is covered with geotextile - great importance is attached to the protection of the USP.

Installation of home communication networks

The project must clearly show how communications - water supply, sewerage and other networks - will pass through the foundation. This is important, since the technology of the platform does not provide for its repair and, therefore, all wiring is arranged in advance.

There is a difficulty - it is necessary to duplicate the circuits in case of blockage. Then during operation it will be enough to turn on the “bypass” while the main circuit is being repaired. The laid communications are covered with sand, which must be compacted manually - with a vibrating plate, for example.

Thermal insulation

It's time to warm up. For this, different materials are used - penoplex, technoplex, styrex and others. They are foamed slabs of extruded polystyrene, which have excellent heat capacity characteristics. The work goes quickly, since the weight of one slab is insignificant.

The styrenes are laid in two layers. Each is laid using plywood floor technology, when the joints of the first layer fall on the plane of the second. Also, you cannot combine the joints of one row with a similar installation of the adjacent one. That is, the work is carried out in a staggered manner.

The fastening is done with special plastic nails with wide heads. We must not forget about laying styrene sheets on part of the blind area and plinth - small protrusions of the sheets will help to “adhere” the material.

Reinforcement and installation of heated floors

Regardless of the desire to make or not make warm floors, the reinforcement is done in two layers. The first is a grid on which the system's collectors will be laid in the future. Still, USP technology is more productive in tandem with heated floors, so after distributing the wiring, the system is pressurized and checked.

Afterwards the second layer of armored belt is laid.

It is important - you cannot weld the rods together - only knit them.

High temperatures are detrimental to the composition of steel and consequences in the form of loss of rigidity are guaranteed.

Formwork for USP

The formwork is classic, using plywood panels and supports to hold the mass. The walls from the inside are lined with the same polystyrene; subsequently, when removed, a surface is formed identical to the plane of the foundation, ready for further processing.

To construct the formwork, you don’t have to purchase special plywood; flat boards are fine. They are used in subsequent construction, since they are free of concrete.

Pouring concrete

The final stage of construction of the Swedish insulated slab - pouring concrete - is carried out in one go. It is allowed to use the mass in portions with an interval of 1 hour, no more.

Automatic tamping with a vibrating plate must be used. Since a perfectly flat surface is rarely achieved, the finished slab is ground. Otherwise, you will have to lay a leveling screed. After three days, the wooden panels are removed.

Caring for the stove until it is ready is standard. Watering during hot periods and covering with PVC film.

Simple but precise execution in accordance with the described steps guarantees a high-quality platform for a country house.

In low-rise construction, you can do without pouring a monolithic concrete foundation and create a reliable, warm foundation for the future building. This opportunity is provided by foundations made using technology USP.

The abbreviation stands for insulated Swedish stove, which is effectively used in European countries. The technology became known in Russia since 2009, but is currently not widely used - developers are just beginning to master it.

The lack of interest is caused by the lack of complete and reliable information about this type of foundation. At first glance, the technology seems complex and expensive. In fact, the cost of the work turns out to be lower than pouring a conventional monolithic concrete slab.

Structure of an insulated Swedish plate

The data in the article is purely informative and does not constitute instructions for arranging a USP foundation: it requires precise engineering calculations that are tied to a specific building site.

There are several arrangement options, but the differences are personal in nature and do not affect the overall installation technology. In essence, the Swedish foundation resembles a multi-layered cake consisting of the following elements:

soil base with a pre-prepared drainage system;

geotextile substrates;

sand and gravel pads with areas for sewer pipes and utilities;

insulating layer;

waterproofing;

second layer of insulation;

fittings and underfloor heating systems;

concrete slab (average thickness 100 mm);

floor finishing.

At first glance, the design seems bulky and complex, but this is an illusion. All work can be done on your own without the use of heavy construction equipment.

Provided that the work is carried out correctly at all stages, a solid foundation is obtained, with stiffening ribs and a properly installed heating system. This design completely prevents possible heat loss and at the same time has a high load-bearing capacity.

Advantages and disadvantages

Pipes do not require additional insulation.

Reliable protection against groundwater exposure.

Possibility of building a foundation on all types of soil, except rocky.

Reduced heating costs due to the “warm floor” system.

You can do without the use of bulky construction equipment.

Acceleration of the process - the full cycle from preparing the base to finishing takes no more than two weeks.

Uniform load distribution, resistance to deformation.

Inability to eliminate errors made during the construction process.

The need for backup communications.

There is no possibility to make a basement and ground floor.

Some of the shortcomings can be eliminated if you entrust the work to qualified designers and workers. However, attracting specialists makes the financial benefits less attractive.

USP or monolithic foundation?

At first glance, the economic benefit of arranging a USP is invisible - a large amount of building materials are required, which cost some money. The estimate includes the purchase of:

insulation;

fittings;

floor insulation systems;

other materials.

When pouring a monolithic foundation, such expenses are not required: the base is prepared, reinforcement is purchased, piping is done and concrete is poured. However, the financial benefits of pouring a monolith are understandable only to non-professionals.

Such a foundation can be compared to a bank loan: there are not enough funds - fill the site, and then gradually build further. The process turns out to be extended over time, which implies an increase in the price of building materials. In addition, the monolithic foundation needs insulation and waterproofing; utilities will also be supplied to the building.

USP is suitable for people who understand the benefits of such a design and are building a house that will be warm and cozy regardless of the vagaries of the weather. If you make calculations on energy savings for 10 years forward, the attractiveness of an insulated foundation will increase. Against this background, a monolithic foundation looks like an ordinary slab, which requires additional investment.

Step-by-step technology for arranging USP

The work process begins with the involvement of technical specialists who can calculate the bearing capacity of the soil, the likelihood of shifting layers and the capabilities of the drainage system. After this, the construction of the foundation is carried out in a certain sequence.

The Swedish foundation is never laid on a fertile layer of soil: this is guaranteed to lead to a shift in the structure during the construction of the building. Therefore, such a layer of soil is completely removed from the construction site.

The pit is made shallow: usually 2-3 bayonet shovels, however, its external dimensions should extend one meter beyond the boundaries of the walls of the future building. The bottom of the pit is lined with geotextiles with the substrate running onto the side walls.

Storm drainage and groundwater drainage are necessary to ensure a dry foundation. For these purposes, geotextiles are covered with a layer of crushed stone, and an underground reservoir is made with pipes connected to it. To lay the drainage system along the perimeter of the pit, trenches are formed with a slope towards the main well.

Utility lines

The next stage is the installation of water supply and sewerage pipes. Communications must be buried below the ground freezing mark in winter.

In addition, it is necessary to plan in advance the location of the risers in the house, to bring the pipes outside for connection to centralized or autonomous water supply systems.

Considering the shortcomings of USP, it makes sense to immediately duplicate the communication system in order to use reserves in case of a malfunction. At this stage, a sand cushion is added, which is necessarily compacted with a tamping machine.

The first layer covers the entire perimeter of the pit.

The second one retreats by 40-45 cm inside.

This is necessary in order to install along the edges L-shaped modules made of polystyrene foam for external contour.

At this stage, the installation of the “warm floor” system is carried out with the installation of collectors and temporary pressure testing of pipes. Next, a two-layer reinforcing belt is made from reinforcement with a diameter 12-16 mm. Recommended grid pitch 15*15 cm.

Manufacturing of formwork

For this they can be used L-shaped modules expanded polystyrene, reinforced on the outside with boards and spacers to prevent them from being squeezed out under the action of the concrete mass. The classic version can also be used: an internal frame made from panels of thick plywood. The height of the formwork is calculated based on the following values: insulation thickness (20-30cm) and the slab itself (no more than 10 cm).

This stage is no different from the arrangement of a monolithic foundation. The concrete mixture is supplied continuously to prevent the formation of joints and is necessarily compacted with deep vibrators to uniformly fill the internal space.

Keep in mind that contact of the vibrator with “warm floor” pipes or reinforcing mesh is extremely undesirable.

Formwork can be removed after 72 hours after filling. If work is carried out in hot weather, the slab is covered with burlap or plastic film and periodically moistened with water. In winter, a heating system is installed before pouring.

Even before the advent of high-strength insulation materials, solid slab foundations were considered an effective means of compensating for seasonal (frost heaving) and non-seasonal soil movements. Being “floating”, they maintained the relative position of all elements of building structures relative to each other, even when houses fell into areas of small landslides. An original engineering innovation that combined the solution to energy efficiency problems was the so-called USP foundation, the technology of which came to us from Sweden and Germany. This article describes the design and operational features of the insulated Swedish stove (as the abbreviation “USHP” stands for).

About 10 years ago, the first domestic enthusiasts, developers, used standard projects from this particular company. According to Dorocell, the optimal energy-efficient foundation for low-rise housing construction is a high-quality monolithic concrete slab with stiffeners, external thermal insulation and built-in heating.

Scheme of the technology for installing an insulated Swedish USHP plate using TechnoNIKOL materials

Thermal insulation, representing a kind of “trough” for pouring concrete, serves as a natural permanent formwork.

Here is a detailed overview of the foundation of an insulated Swedish slab:

Formwork made of polystyrene PSB-S is assembled on a compacted sand and crushed stone bedding. At the bottom of the backfill bed, slopes were made and a drainage pipe was installed.
Formwork 400 mm high consists of slabs 100 mm thick and forms rectangular grooves with a cross-section of 400×200 along the perimeter to form stiffeners and a bed for pouring the main slab 100 mm thick.
Reinforcement of the ribs is carried out in two belts with a profile of variable section with a diameter of 8 - 12 mm. Reinforcement of the floor slab is carried out using a welded mesh 150x150 mm.
The heating system pipelines are embedded in the floor slab. The floor slab is reinforced using a 150×150 mm welded mesh laid on top of the heated floor pipes.
In addition to the heated floor, other communications are also poured with concrete - water supply, sewerage, electrical wiring in the rooms.
Insulation of the blind area is carried out along the perimeter of the foundation with 70 mm PSB-S slabs adjacent to the polystyrene formwork from the outside at the depth of its contact with the bedding.

Thermal insulation skirt around the foundation slab protects against freezing

The described scheme corresponds to the load generated by a two-story house with load-bearing walls made of cellular concrete, as well as climatic conditions with a frost index of 4000 - 8000. An increase in load requires an increase in the cross-section of the stiffeners, and a more severe temperature regime requires the addition of one or two additional layers of insulation.

There is an alternative technology for installing an insulated foundation: UFF - insulated Finnish slab. An overview and features of this type of foundation are described in

The best video about USP technology

Pros and cons of the Swedish stove

The most important thing is that as a result of installing the foundation according to the warm Swedish stove scheme, the developer receives a solution to a whole range of issues:

effective drainage,
anti-frost protection,
energy saving,
heating,
comfortable microclimate,
laying communications,
as well as obtaining a floor surface for finishing coatings.

Other benefits of the scheme include:

For frame houses, USHP compensates for their main drawback - the low heat capacity of the walls. A massive insulated foundation takes on the function of a backup heat accumulator.
Price. Despite the fact that the Swedish scheme is not a cheap pleasure, it includes not only the zero cycle, but a whole set of stages. Performing these works separately costs significantly more in total.
Deadlines. When the work is carried out by a team of qualified specialists, everything will take, on average, about a week.
Versatility. The technology is suitable for most soils and climatic zones of the Russian Federation.
Indispensable in the construction of “passive house” class buildings.

Disadvantages of a foundation based on a warm Swedish stove:

Conditional (psychological) disadvantage: low base. In houses with a regular foundation, a high base is necessary to ensure normal humidity in the rooms. Until now, many of our compatriots tend to consider the height of the basement as one of the guarantees of housing quality.
Maintainability of communications. Since the floor slab is a stressed structure, it is extremely undesirable to violate its integrity to repair bricked up pipelines. On the other hand, there are other installation methods and technical solutions that compensate for the shortcomings of the circuit. But all these measures lead to an increase in costs.
Requires highly qualified performers. Not every team will take on the turnkey delivery of the USP.
It requires significant one-time capital expenditures, therefore it is not suitable for developers who expect construction in small (in terms of money) stages.
Not suitable for peaty soils and other soils with low bearing capacity, as well as areas with large slopes.

Technology development: methods, materials, components

To date, more than 1.5 million houses have been built using the USP scheme in Germany and the Scandinavian countries. In Northern Europe technology insulated monolithic slab foundation received generally accepted status and is reflected in EU building standards. In the USA, complete external insulation of slab foundations is not widespread, since 90% of the country has a frost index of no more than 3000. However, USP has also found application there: first of all, in the construction of “passive houses”.

Over the past 10 years, project developers have given greater preference to extruded polystyrene foam (EPS) as a material that provides more uniform shrinkage of foundations and maintains thermal insulation properties regardless of time and operating conditions. The stresses in concrete arising during the operation of shallow slab foundations were studied in detail. Based on their results, builders abandoned the idea of using insulation materials with different ultimate strengths (previously it was assumed that in order to equalize shrinkage under the floor slab, it was necessary to use less strong slabs than under the stiffeners). It has been proven that the most dangerous stress concentrators in a slab can occur at the junction of different types of heat insulation.

Manufacturers of extruded polystyrene foam began to produce materials and components specialized for the installation of USP.

For example, Dorocell itself currently produces a complete set of “designer” parts for permanent formwork made of EPS. The company's calling card is blocks with built-in guides for fittings. Some brands pay increased attention to the aesthetic properties of the components: the sides of the formwork are molded in the form of plinths of a traditional variable section.

If we talk about the domestic market, then there are 2 brands on the market: TechnoNIKOL and Penoplex. Both companies produce EPS of European quality level for slab foundations built using USHP technology. I would like to dwell in more detail on the specialized series TECHNONICOL CARBON ECO SP. In addition to the basic slab formats, it includes L-shaped profiles for quick installation of sides. In addition to the cross-section, these elements are interesting because CSP (cement-bonded particle boards) are fixed to their base parts on the outside. DSPs allow you to apply decorative plaster without additional preparatory stages. Thus, installation of USP using TechnoNIKOL components is currently the most convenient.

Algorithm for installing an insulated slab foundation

For a full cycle of work on arranging the USP, you will need the following basic materials:

Geotextiles;
100 mm EPS slabs for formwork and 70 mm slabs for insulating the blind area;
fittings Ø12; welded mesh 150×150;
Concrete grade not lower than M350 with the necessary additives, taking into account the pouring time and air temperature, anti-capillary crushed stone, coarse sand;
Pipes of the PEX or P-PE type for a pressure of at least 6 bar at a coolant temperature of up to +95°C, as well as a protective corrugation;
1"" collectors (for a house with an area of no more than 250 sq. m., in most cases, 2 pieces are needed);
Shut-off valves consisting of Eurocone compression fittings, 1" ball valves and a system crimping unit;
Special fasteners consisting of disc-shaped dowels, studded plates, FS-30/40 clamps, double-sided tape.

After completing geological surveys, strength calculations and purchasing materials, the future foundation is marked. Based on the addition of 0.3 - 0.5 m to the edge of the insulated blind area, the perimeter is determined. The axes of the internal load-bearing walls are marked, as well as the points and directions for laying communications. Further work is carried out as follows:

Removing fertile soil;
Laying geotextiles along the bottom with overlapping joints of at least 15 cm;
Layer-by-layer backfilling with crushed stone and sand is carried out. Each layer of 10 - 15 cm is compacted with a vibrating plate with added water for greater compaction;
Laying communications - water supply, sewerage, power cables, ground loop, drainage system. When laying sewer lines, ensure slopes. When arranging drainage, in addition to observing slopes, provide drainage wells. Check the operation of the slopes with water.
Backfill drainage and sewer trenches and check the overall plane of the backfill pad.
Start assembling the insulating formwork. If L-shaped profiles are not used, then you will need to do a significant amount of work. First, the slabs are glued end to end at an angle of 90° using a special glue. For additional fastening, disc dowels and plastic fastening corner elements are used. Secondly, the resulting sides need to be fixed from the outside with plywood or boards, supporting them with slats.
Starting from the second or third layer of polystyrene, niches for stiffeners are formed during installation. The slabs are laid in a horizontal plane “in a staggered manner”, with the joint line offset.
If necessary, a vapor barrier layer is laid on top of the last layer of EPS.
Let's start reinforcing the stiffeners. Reinforcement is provided by four longitudinal reinforcement bars Ø 10 - 12 mm, forming the upper and lower chords. The load-bearing frames are connected using special clamps outside the formwork. The finished power units are installed in the grooves and secured using FS clamps.
Using the same clamps, a 150x150 mesh is mounted for the floor slab (rod diameter 6 - 10 mm).
Heated floor pipes are installed over the laid mesh and secured with nylon clamps. When crossing stiffeners and doorways, pipes must be protected with corrugations.
After installing all the heated floor circuits, they are connected to the collector. The places where pipes rise to the collector are protected by corrugation.
Each circuit is filled with coolant separately. Filling is carried out through the manifold until all air is displaced from the system. Then leak tests are carried out. After testing, it is necessary to crimp all connectors of the system.
Before concreting, it is necessary to check the structure. The check consists of control measurements of the formwork, inspection of the reinforcement, clearing the site of debris, protecting communication terminals from concrete, as well as checking the fixation of these terminals on the formwork. At the end of the preparation, the entire initial situation with the location of communications should be captured in detailed photographs and an internal inspection report of the formwork and engineering systems should be signed.
We select a concrete supplier and order him a mixture with the properties required by the project.
On the day of concreting, large equipment (mixer, concrete pump) is placed, the mixture is accepted for quality, the mixture is laid and maintained. Laying work is carried out in accordance with the standard for carrying out this type of work in compliance with working methods and time intervals. During installation, it is necessary to carefully monitor the flow of mortar under the reinforcement elements. The surface is leveled using vibrating slats. Vibration processing of the incoming mixture is provided in the stiffeners. In order to ensure the required dehydration regime, the concrete is covered with polyethylene film.
In the future, it is necessary to monitor the progress of dehydration and check the surface for a strength gain of 15 kgf/cm2. This indicator makes it possible to carry out other construction work at the site.
While the concrete is gaining strength, you can organize cleaning of the area and lining the outer surface of the base with finishing material.
After covering the base, it is necessary to organize a blind area. It is recommended to lay a drainage membrane on top of the blind area slabs. At the end of the work, the blind area is backfilled.

What stages of installing an insulated Swedish stove are acceptable and advisable to do yourself? If you do not have experience in carrying out the types of work described, then you can only recommend paragraphs for doing it yourself. 2; 6; 7; 8; 10; 14; 15; 17; 18; 19.

Persons who have the necessary skills, but work alone at their site, are allowed to carry out all types of work except concreting. An exception may be objects with a small area (up to 30 - 40 sq. m.).

A construction innovation is the Swedish slab - a foundation whose technology is of European origin. The foundation is the support of any building. It is with its installation that the construction of the house begins. Today, many foundation construction technologies are used, but the search and improvement of new developments never stops. The relatively easy method of making a Swedish slab does not require the use of serious construction equipment and is completely doable with your own hands.

You will not need to carry out additional work on pouring screed or leveling the floor, since the slab itself is already a subfloor. Laying the flooring on top is all that is required of you at the final stage.

This foundation is optimal for country house or low-rise construction. The use of modern technologies and building materials allows us to lay a high-quality foundation in a short time, in which all the required communications will be located. Arranging such a foundation (Swedish slab) takes much less time than installing a strip or pile foundation.

DIY Swedish stove

During the work process, pipes for floor heating are laid in this foundation (water floor technology), and the sewerage and water supply systems pass under layers of insulation. A characteristic feature of this foundation is thermal insulation protection (penoplex, expanded polystyrene), which is laid both below and on the sides of the entire foundation. Thus, the insulation follows the shape of the formwork, and after its dismantling remains in place.

The Swedish foundation consists of layers:

crushed stone (or gravel);
sand;
roofing felt (or thermoplastic film);
extruded polystyrene foam;
reinforced frame;
pipe systems;
repeated layer of reinforced mesh;
concrete layer.

The insulated Swedish stove is perfect for building houses in swampy areas or on soil with close soil water. This type of slab foundation has also proven itself well on weak heaving and bulk soil types. This foundation is not afraid of any manifestations of chemical aggression of the soil or frost heaving, thanks to the chemically inert polystyrene foam, which protects it from all sides.

Swedish stove - technology:

During the hardening process, you need to periodically moisten the concrete so that it does not crack. After all the steps taken, you will have an energy-saving foundation “insulated Swedish slab” - USHP for short.

House on a Swedish stove - pros and cons

Any construction process has its pros and cons. Installing a foundation is a serious step, so you need to have an idea of the nuances that you will have to face. After weighing all the pros and cons, you can make the right decision and calculate your capabilities.

Swedish stove - advantages:

Such a foundation has excellent energy-saving characteristics; in fact, it is a heat storage device for your home. Your floor will be warm at any time of the year.
All communication systems are installed in the base of the slab - this optimizes the construction process of the house as a whole.
There are no shrinkage or expansion joints - an important aspect - the key to the “longevity” of the foundation.
This foundation is the ideal base for laying any floor covering. The surface for the finished floor will already be level, since the concrete is poured level.
On such a foundation you can build any type of structure. Frame or panel house, block, stone, brick buildings, log houses - any residential structures with a maximum of 3 floors.
Depending on the size of the house, the overall construction time is significantly reduced. Such a foundation is built quite quickly. After about a month, you can begin to build the walls of the house.
If you have an insulated Swedish stove as your foundation, problems with dampness and various fungi will not affect you. A heated foundation is not only a comfortable comprehensive solution, but also a rational one.

Using a built-in water floor system will provide heat not only inside the house, but will not allow the soil underneath to freeze. The thermal conductivity of such a foundation is 3-4 times lower than that of a standard foundation.

A warm slab is a foundation with many advantages, but it would be fair to highlight the so-called disadvantages of this technology. It should be taken into account that most of the disadvantages described below also apply to other slab-type foundations.

The first thing that comes to mind is the cost of constructing the foundation, but they cannot be defined as a minus, because in the perspective of the side costs of installing heating, they rather look like a plus.

Swedish stove - cons:

This type of foundation is designed for construction on a flat piece of land. If the terrain has a slope, then all construction stages will cost you a large sum.
Almost all types of soil are suitable for such a foundation, but soil with very low bearing capacity (for example, peat) is not suitable for such a foundation.
If your future home is expected to be large in size and have a complex construction project, then you will need qualified craftsmen with experience in such work to get involved. A truly good master, as you know, is not so easy to find.
Be prepared for the floor level to be equal to the ground level behind the wall of the house. If a monolithic Swedish slab is on average 30-40 cm, then with such a foundation you will have a low base.
The cost of modern, mostly imported materials.
It should be remembered that this type of foundation is not designed for large, heavy buildings.
Access to repair of communications - this factor cannot be excluded, despite the fact that the operational life of many modern communication systems is quite long. No matter how reliable and well-thought-out the insulated Swedish stove is, sewerage and water supply problems, alas, can occur. Finding access to integrated engineering communications and ways to solve the problem will cost a considerable amount.

When starting to build such a foundation, calculate all the nuances and construction stages. Use only high-quality materials, because we build houses not for a couple of years, but for many years.

The Swedish stove is a modern and warm foundation; it will provide an ideal microclimate inside, eliminate the appearance of dampness, and the house itself will not settle or crack.